In connecting a semiconductor device employing a film carrier to an outer substrate such as a package substrate or a case (outer lead bonding), a linear connecting lead formed on the film carrier of the semiconductor device and made of an electroconductive metal such as copper has been and is being utilized. For example, as shown in FIG. 11, when a semiconductor device in which a connecting lead 4 formed on a film carrier 3 has been connected with a semiconductor element 1 through a bump 2 is mounted on an outer substrate 5, a metallic wiring (land part) 6 formed on the surface of the outer substrate 5 and the connecting lead 4 on the film carrier 3 are utilized.
However, such a mounting method is disadvantageous in that its working efficiency is low because the connecting lead 4 is required to be cut or bent and that connection itself is not easy. In addition, the connecting lead 4 has poor mechanical strength because it projects from the film carrier, so that there are cases where the mounted semiconductor device fails to have a connecting strength sufficient to withstand mechanical or thermal shocks and, as a result, the mounted semiconductor device has poor reliability in electrical connection. In connecting the connecting lead 4 with the land part 6, thermal junctioning techniques such as a solder reflow method are usually employed. According to such techniques, in the case of mounting a semiconductor device on, for example, a metal oxide-based transparent electrode such as a liquid-crystal panel, it is necessary that the surface of the transparent electrode is metallized beforehand so as to enable soldering.
In recent years, various methods have been proposed in which the film carrier of a semiconductor device is junctioned with an outer substrate by means of an anisotropically electroconductive film or coating in order to attain a high connecting strength. Any of these methods, however, is defective in that the mounted semiconductor device, if it is of a multiple pin type with a small gap between pins, has a fear of the occurrence of interpin leak and that the products are expensive.